Noninvasively determined muscle oxygen saturation is an early indicator of central hypovolemia in humans.

Ten healthy human volunteers were subjected to progressive lower body negative pressure (LBNP) to the onset of cardiovascular collapse to compare the response of noninvasively determined skin and fat corrected deep muscle oxygen saturation (SmO2) and pH to standard hemodynamic parameters for early detection of imminent hemodynamic instability. Muscle SmO2 and pH were determined with a novel near infrared spectroscopic (NIRS) technique. Heart rate (HR) was measured continuously via ECG, and arterial blood pressure (BP) and stroke volume (SV) were obtained noninvasively via Finometer and impedance cardiography on a beat-to-beat basis. SmO2 and SV were significantly decreased during the first LBNP level (-15 mmHg), whereas HR and BP were late indicators of impending cardiovascular collapse. SmO2 declined in parallel with SV and inversely with total peripheral resistance, suggesting, in this model, that SmO2 is an early indicator of a reduction in oxygen delivery through vasoconstriction. Muscle pH decreased later, suggesting an imbalance between delivery and demand. Spectroscopic determination of SmO2 is noninvasive and continuous, providing an early indication of impending cardiovascular collapse resulting from progressive reduction in central blood volume.

[1]  A. A. Stratonnikov,et al.  Evaluation of blood oxygen saturation in vivo from diffuse reflectance spectra. , 2001, Journal of biomedical optics.

[2]  J. Severinghaus.  Simple, accurate equations for human blood O2 dissociation computations. , 1979, Journal of applied physiology: respiratory, environmental and exercise physiology.

[3]  Babs R. Soller,et al.  Standardization method for correcting spectral differences across multiple units of a portable near-infrared-based medical monitor , 2005, SPIE BiOS.

[4]  S. Simsir,et al.  Noninvasive, near infrared spectroscopic-measured muscle pH and Po2 indicate tissue perfusion for cardiac surgical patients undergoing cardiopulmonary bypass* , 2003, Critical care medicine.

[5]  W. Shoemaker,et al.  Transcutaneous oxygen and CO2 as early warning of tissue hypoxia and hemodynamic shock in critically ill emergency patients , 2000, Critical care medicine.

[6]  H. Barcroft,et al.  POSTHÆMORRHAGIC FAINTING: STUDY BY CARDIAC OUTPUT AND FOREARM FLOW , 1944 .

[7]  D. Delpy,et al.  Performance comparison of several published tissue near-infrared spectroscopy algorithms. , 1995, Analytical biochemistry.

[8]  J. A. Majde.  Animal models for hemorrhage and resuscitation research. , 2003, The Journal of trauma.

[9]  Victor A Convertino,et al.  Arterial pulse pressure and its association with reduced stroke volume during progressive central hypovolemia. , 2006, The Journal of trauma.

[10]  Robert Wise,et al.  The PULSE initiative: scientific priorities and strategic planning for resuscitation research and life saving therapies. , 2002, Circulation.

[11]  David A Ludwig,et al.  Stroke volume and sympathetic responses to lower-body negative pressure reveal new insight into circulatory shock in humans , 2004, Autonomic Neuroscience.

[12]  K H Wesseling,et al.  Effects of peripheral vasoconstriction on the measurement of blood pressure in a finger. , 1985, Cardiovascular research.

[13]  G. Gutierrez,et al.  Clinical review: Hemorrhagic shock , 2004, Critical care.

[14]  M. Ferrari,et al.  Principles, techniques, and limitations of near infrared spectroscopy. , 2004, Canadian journal of applied physiology = Revue canadienne de physiologie appliquee.

[15]  W. Colier,et al.  Adipose tissue thickness affects in vivo quantitative near-IR spectroscopy in human skeletal muscle. , 2001, Clinical science.

[16]  G. Parati,et al.  Comparison of Finger and Intra‐arterial Blood Pressure Monitoring at Rest and During Laboratory Testing , 1989, Hypertension.

[17]  D. G. Newman,et al.  The non-invasive assessment of stroke volume and cardiac output by impedance cardiography: a review. , 1999, Aviation, space, and environmental medicine.

[18]  W. S. Sageman,et al.  Reliability and precision of a new thoracic electrical bioimpedance monitor in a lower body negative pressure model. , 1999, Critical care medicine.

[19]  K H Wesseling,et al.  Non-invasive continuous finger blood pressure measurement during orthostatic stress compared to intra-arterial pressure. , 1990, Cardiovascular research.

[20]  T. Fukunaga,et al.  Influence of adipose tissue thickness on near infrared spectroscopic signal in the measurement of human muscle. , 1996, Journal of biomedical optics.

[21]  Michelle R. Landry,et al.  Simultaneous correction of the influence of skin color and fat on tissue spectroscopy by use of a two-distance fiber-optic probe and orthogonalization technique. , 2005, Optics letters.

[22]  R. Bellamy.  The causes of death in conventional land warfare: implications for combat casualty care research. , 1984, Military medicine.

[23]  J. Karemaker,et al.  Continuous non-invasive blood pressure monitoring: reliability of Finapres device during the Valsalva manoeuvre. , 1988, Cardiovascular research.

[24]  G. Beilman,et al.  Near-infrared spectroscopy measurement of regional tissue oxyhemoglobin saturation during hemorrhagic shock. , 1999, Shock.

[25]  C. Schulman,et al.  Can near-infrared spectroscopy identify the severity of shock in trauma patients? , 2005, The Journal of trauma.

[26]  Babs R. Soller,et al.  Partial Least-Squares Modeling of Near-Infrared Reflectance Data for Noninvasive in Vivo Determination of Deep-Tissue pH , 1998 .

[27]  Michelle R. Landry,et al.  Quantitative measurement of muscle oxygen saturation without influence from skin and fat using continuous-wave near infrared spectroscopy. , 2007, Optics express.

[28]  J. Puyana,et al.  Simultaneous measurement of hepatic tissue pH, venous oxygen saturation and hemoglobin by near infrared spectroscopy. , 2001, Shock.

[29]  J. Puyana,et al.  Application of fiberoptic sensors for the study of hepatic dysoxia in swine hemorrhagic shock , 2001, Critical care medicine.

[30]  Kathy L Ryan,et al.  Lower body negative pressure as a model to study progression to acute hemorrhagic shock in humans. , 2004, Journal of applied physiology.

[31]  Victor A Convertino,et al.  Heart rate variability and spontaneous baroreflex sequences: implications for autonomic monitoring during hemorrhage. , 2005, The Journal of trauma.

[32]  R. Patterson,et al.  Development and evaluation of an impedance cardiac output system. , 1966, Aerospace medicine.

[33]  Babs R Soller,et al.  Removal of Analyte-Irrelevant Variations in Near-Infrared Tissue Spectra , 2006, Applied spectroscopy.

[34]  A. Peitzman,et al.  Hemorrhagic shock. , 1995, Current problems in surgery.

[35]  P. Raven,et al.  Noninvasive assessment of sympathetic vasoconstriction in human and rodent skeletal muscle using near-infrared spectroscopy and Doppler ultrasound. , 2004, Journal of applied physiology.

[36]  A. Sauaia,et al.  Epidemiology of trauma deaths: a reassessment. , 1993, The Journal of trauma.